Bad Physics Teach!

I am in grade 11 Physics, and have a question that I need to solve. My teacher has repeatedly said that he hates physice, "I don't wanna teach it, and you don't wanna learn it", and offers virtually no help, yet assigns massive ammounts of work! :surprised I have over 100 questions (in this same format to do), I was wondering if I have an example, someone could walk me through it, so that I can do the rest. I've had many attempts, and every time that I had shown him, he has just said "nono, Look it up in the text book". Thanks again, Here's the quetion.

A rollercoaster accelerates from 0-160 km/h in 7 seconds. Calculate the average acceleration in:

First of all, I think you should report this guy to his boss. He is being paid to do a job.

Second, we do have a requirement here at PF that you show an attempt at the problem (the notice at the top of this Forum). So if you'd be so kind as to post what you think is the best of your "many attempts", we'd appreciate it. Then we can explain what is going wrong.